深入浅出，camera v4l2理解（1）v4l2准备使用的参数

 

1，probe

2，读id，id读完了并且成功才能注册v4l2

 

3，注册v4l2，

v4l2_i2c_subdev_init(&s_ctrl->sensor_v4l2_subdev, client,s_ctrl->sensor_v4l2_subdev_ops);

这里v4l2的注册需要几个参数

s_ctrl->sensor_v4l2_subdev

这个参数主要是v4l2的名字，这个name是从驱动中去读的，如下

snprintf(s_ctrl->sensor_v4l2_subdev.name,sizeof(s_ctrl->sensor_v4l2_subdev.name), "%s", id->name);

client

这个参数是i2c的client，从驱动中获取，读id的时候使用的那个

s_ctrl->sensor_v4l2_subdev_ops

这个参数是驱动中的imx111_subdev_ops

static struct v4l2_subdev_core_ops imx111_subdev_core_ops = {

  .ioctl                     = msm_sensor_subdev_ioctl,   //各种效果等控制参数的传递

  .s_power                   = msm_sensor_power,          //power

};

static struct v4l2_subdev_video_ops imx111_subdev_video_ops = {

  .enum_mbus_fmt             = msm_sensor_v4l2_enum_fmt,

};

static struct v4l2_subdev_ops imx111_subdev_ops = {

  .core                      = &imx111_subdev_core_ops,   //见上面

  .video                     = &imx111_subdev_video_ops,  //见上面

};

int32_t msm_sensor_v4l2_enum_fmt(struct v4l2_subdev *sd, unsigned int index,

                        enum v4l2_mbus_pixelcode *code)

{

       struct msm_sensor_ctrl_t *s_ctrl = get_sctrl(sd);   //这边不用说，还是驱动那个s_ctrl

       if ((unsigned int)index >= s_ctrl->sensor_v4l2_subdev_info_size) //这里就是看你准备了多少种code，看看是不是超出了所定义的  

              return -EINVAL;

       *code = s_ctrl->sensor_v4l2_subdev_info[index].code;   //调用驱动中的code

       return 0;

}

static struct v4l2_subdev_info imx111_subdev_info[] = {       //这个在驱动里面，就是上面的那个info

  {

    .code                    = V4L2_MBUS_FMT_SRGGB10_1X10,

    .colorspace              = V4L2_COLORSPACE_JPEG,

    .fmt                     = 1,

    .order                   = 0,

  },

};